The Clinical Services and Diagnostics Core of the proposed Center represents a unique resource that is organized around the recruitment, characterization and rigorous diagnostic evaluation of first-episode, antipsychotic-naive schizophrenia and non-schizophrenia psychotic subjects, and healthy controls, and the acquisition of clinical data and diagnoses of subjects used in postmortem studies. Clinical research studies conducted in the proposed Center will use multimodal electrophysiological methods, functional neuroimaging (fMRI) approaches (Project 5-Phillips), and a novel PET method (Project 6-Mathis) to test hypotheses regarding the relationships between cortical neuronal network activity, GABA neurotransmission and information processing deficits in schizophrenia. The Core integrates and coordinates the recruitment and assessment of subjects across projects within the proposed Center as well as for other funded collaborative projects to ensure that subjects are efficiently and productively engaged with a minimum redundancy of activities. The clinical and diagnostic expertise of Core faculty and staff is also utilized in the characterization of the clinical research diagnoses of individuals whose post-mortem brain specimens are used in Project 1- Lewis. The infrastructure of the Clinical Services and Diagnostics Core also serves as an educational opportunity for young investigators to develop seed proposals to address questions relating to the pathophysiology of schizophrenia, and as a means to educate the practicing clinicians, students, and the general public about advances in schizophrenia research.